EP1388217A2

EP1388217A2 - Transmission power level estimation

Info

Publication number: EP1388217A2
Application number: EP02725944A
Authority: EP
Inventors: Eldad Zeira; Guodong Zhang
Original assignee: InterDigital Technology Corp
Current assignee: InterDigital Technology Corp
Priority date: 2001-05-15
Filing date: 2002-05-07
Publication date: 2004-02-11
Anticipated expiration: 2022-05-07
Also published as: KR20080059291A; NO20035050D0; KR20050091102A; KR20030094416A; CN1526207A; MXPA03010486A; JP2009010976A; CA2447241C; TWI255101B; TWI272787B; DK1494367T3; EP1494367B1; KR100865100B1; KR20090042844A; JP2007104693A; TW200618517A; KR20070055631A; TW200729770A; CN1801676A; JP4521388B2

Abstract

A model for noise rise of users in relation to an interference measure, a pathloss and a desired signal to interference ratio is provided. For a selected user, a pathloss, an interference measure and a desired signal to interference ratio is determined. A noise rise for the selected user is determined using the determined interference measure, pathloss, desired signal to interference ratio and the noise rise model. The selected user transmission power level is estimated using the determined noise rise.

Description

[0001] TRANSMISSION POWER LEVEL ESTIMATION

[0002] BACKGROUND

[0003] The invention generally relates to wireless communication systems. In

particular, the invention relates to estimating transmission power levels in such

systems.

[0004] Figure 1 depicts a physical layout of a wireless communication system.

The system has a plurality of base stations 20. Each base station 20 communicates

with user equipments (UEs) 22 in its operating area or cell 23. Communications

transmitted from the base stations 20 to the UEs 22 are referred to as downlink

communications and communications transmitted from the UEs 22 to the base stations

20 are referred to as uplink communications.

[0005] A network perspective of a wireless communication system is shown in

Figure 2. Each node-B 24 within the system communicates with associated UEs 22

or users. Each node-B 24 has a single site controller (SC) 34 associated with either

a single or multiple base stations 20. A group of node-B s 24 is connected to a radio

network controller (RNC) 28_J. To transfer communications between RNCs 28, an

interface between the RNCs (IUR) 26 is utilized. Each RNC 28 is connected to a

mobile switching center (MSC) 30 which in turn is connected to the core network 32.

[0006] In code division multiple access (CDMA) communication systems,

multiple communications can be sent over the same spectrum simultaneously. The multiple communications are distinguished by their codes. In time division duplex

communication systems using CDMA (TDD/CDMA), the spectrum is time divided

into repeating frames having time slots, such as fifteen time slots. In such systems,

communications are sent in selected time slots using selected codes. A physical

channel is defined as one code in one time slot. The use of a single code in a single

time slot with a spreading factor of sixteen is referred to as a resource unit. Based on

the type of service being provided to a user (UE 22) in the system, one or multiple

physical channels may be assigned to support the users uplink and downlink

communications .

[0007] Since multiple communications are simultaneously carried over the same

frequency spectrum, one user's communications may interfere with another user's. To

reduce such interference, transmission power control is used. In transmission power

control, a transmission is sent at a power level so that only a desired reception quality

is met, such as a signal to interference ratio (SIR), bit error rate (BER) or block error

rate (BLER).

[0008] One transmission power control technique is open loop power control.

In open loop power control, a transmitter's power level is determined using a pathloss

estimate between the transmitter site and its desired receiver site. To estimate the

pathloss, the receiver site transmits a signal and an indicator of the transmission power

level of the signal. By subtracting the received power level from the transmitted

power level of the signal, the pathloss is estimated. Using the pathloss estimate and

a target signal to interference ratio (SIR), a transmission power level for the transmitter is set. The value of the target SIR is based on the service type. Another

type of power control is closed loop power control. Closed loop power control sends

power commands from the receiver site to adjust the transmitter's power level.

[0009] When a new user or user service is added to a system, the new user will

create interference to existing users communicating at the same time. To maintain

their desired signal quality, the existing users typically increase their transmission

power levels. However, some transmitters may be near their transmission power

limits. As a result, adding the new user may create an unacceptable quality of service

(QOS) for existing users.

[0010] To evaluate whether a new user should be added to the system, it is

desirable to estimate the transmission power levels of the existing users, after

admission of the new user. If all of the users, including existing and the new user, are

all safely within acceptable transmission power levels, the new user is admitted. If a

user's transmission power level is unacceptable, such as by being over its transmission

power level capabilities, the new user is not admitted.

[0011] Accordingly, it is desirable to have better transmission power

estimations.

[0012] SUMMARY

[0013] A model for noise rise of users in relation to an interference measure,

a pathloss and a desired signal to interference ratio is provided. For a selected user,

a pathloss, an interference measure and a desired signal to interference ratio is determined. A noise rise for the selected user is determined using the determined

interference measure, pathloss, desired signal to interference ratio and the noise rise

model. The selected user transmission power level is estimated using the determined

noise rise.

[0014] BRIEF DESCRIPTION OF THE DRAWING(S)

[0015] Figure 1 is an illustration of a physical layout of a wireless

communication system.

[0016] Figure 2 is an illustration of a network layout of a wireless

communication system.

[0017] Figure 3 is a simplified radio network controller for transmission power

level estimation.

[0018] Figure 4 is a simplified node-B for transmission power level estimation.

[0019] Figure 5 is a simplified user equipment for transmission power level

estimation.

[0020] Figure 6 is a flow chart for determining transmission power levels after

admission for a new user or user service.

[0021 ] Figure 7 is a flowchart of determining transmission power levels using

noise rise.

[0022] Figure 8 is a plot of a simulation of noise rise versus pathloss.

[0023] Figure 9 is a graph of a simulation of noise rise versus mean pathloss. [0024] Figure 10 is a flowchart of compensating for missing pathloss

information.

[0025] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0026] Figure 3 is a simplified RNC 28 for use in transmission power level

estimation. The RNC 28 has a RRM device 36 and a measurement collection device

38. The measurement collection device 38 collects various measurements from other

components of the network, such as the node-Bs 24 and the UEs 22. These

measurements include transmission power levels (both uplink and downlink), pathloss

information and other information. The RRM device 36 uses the measurements in

determining efficient assignment of resources which is sent to the other components.

The RRM device has a transmission power level estimation block 37 for use in

determining the estimated transmission power levels.

[0027] Figure 4 is a simplified node-B 24 for use in transmission power level

estimation. An antenna 40 receives radio frequency signals over a radio channel from

the UEs 22. The received signals are passed through an isolator or switch 42 to a

receiver 46 and a measurement device 48. A channel assignment device 44, which

receives channel assignments from the RNC 28, identifies the physical channels and

time slots to allow the receiver 46 to detect the transmitted data. The receiver 46 may

be a multiuser detection device (MUD), a RAKE or a different type of receiver. The

receiver 46 also recovers signaled information from the UE 22, such as measurement

information, which is relayed to the RNC 28. [0028] A measurement device 48 takes various measurements at the node-B 24,

such as interference levels and reception power levels. These measurements are also

relayed to the RNC 28. A transmitter 50 sends data and signaled information, such

as channel assignments and a transmission power level of the node-B transmitter 24,

to the UEs 22. The channel assignment device 44 determines a transmission power

level for the node-B transmitter 50. The channel assignment device 44 controls the

gain of an amplifier 52 to control the transmission power level. The transmitted

signals pass through the isolator or switch 42 and are radiated by the antenna 40.

[0029] Figure 5 is a simplified UE 22 for use in RRM. An antenna 56 receives

radio frequency signals over a radio channel from the node-B 24. The received

signals are passed through an isolator or switch 58 to a receiver 66 and a measurement

device 68. A channel assignment detection device 44 recovers the signaled

information concerning the UE's channel assignments for both uplink and downlink.

The receiver 66 may be a multiuser detection device (MUD), a RAKE or a different

type of receiver.

[0030] A measurement device 68 takes various measurements at the UE 22,

relayed to the RNC 28 by being transmitted to the node-B 24. A transmitter 70 sends

data and signaling information, such as measurements, pathloss information and a

transmission power level of the UE transmitter 70, to the node-B 24. A transmit

power controller (TPC) 60 determines a transmission power level for the node-B

transmitter 60. The TPC 60 controls the gain of an amplifier 62 to control the transmission power level. The transmitted signals pass through the isolator or switch

58 and are radiated by the antenna 56.

[0031 ] The following is an approach to estimate new transmit power levels for

users in a system after admission of a new user or user service. The system's users use

transmission power control, such as open loop power control, to reduce interference

between users.

[0032] The approach is explained in conjunction with W-CDM A TDD/CDMA

system, where uplink and downlink transmissions are assigned separate time slots. The

approach is also applicable to CDMA systems where uplink and downlink

transmissions are separated by frequency spectrum and other hybrid time division

multiple access (TDMA)/CDMA and TDD/CDMA systems where uplink and

downlink communications are assigned separate time slots or frequency spectrum, by

including the out of band attenuation factor in the pathloss.

[0033] For the analysis, the system as shown in Figure 8 is divided into a region

where for a particular time slot, M UEs 22 are served by N base stations 20. To

simplify the analysis, it is assumed multi-user detection (MUD) receivers are used for

both uplink and downlink reception, although the approach is extendable to other

receivers, such as a RAKE receiver. Each base station 20 is assigned an index, such

as j, where j = 1, 2, . . ., N. Each base station j has a set Ω(j) UEs 22 connected to it.

Each UE 22 is assigned an index, such as i, where i = 1, 2, . . ., M. A new UE 22 or

UE session, UE M + 1, is to be added to the region. UE M + 1 is proposed to be

added to base station N. [0034] For use in determining the transmit power levels for an uplink time slot,

an i^ώ UE's initial uplink transmit power level prior to the addition of the new user is

defined as T°(i), where 0 indicates the initial transmit power level. The new user's

power is determined, such as by Equation 5.

T ,o^υ ( M +1) = PL_M+ - ISCP_{M +Ϊ} - SIR_UL ( M + 1) Equation 5

PL_{M + n} is the pathloss between the M + 1 user and the base station. This value is

typically determined at the base station n by subtracting a received power level of a

signal from the UE 22 from its transmission power level. Alternately, the pathloss is

estimated from other UEs 22 at a similar distance from the base station 20. ISCP_{M +}

, is the interference as measured using interference signal code power (ISCP) at the

UE receiver. This value is either measured at the UE 22 or estimated by ISCP

measurements by other similarly situated users. The ISCP can be replaced in the

analysis with other types of interference measurements. SIRT_JL(M + 1) is the desired

uplink signal to interference ratio at the base station for the M + 1 user.

[0035] The other users initial transmit powers are typically known or are

estimated, T°(l), . . ., T°(M). An initial power vector is constructed (72), such as by

Equation 6. r°(i)

Γ°(2)

T = Equation 6

T° ( M ) T° ( +1)

[0036] Each users power level is iteratively adjusted to generate an estimate of

the transmission power levels that each user will reach at equilibrium after

introduction of the new user M + 1.

[0037] The ISCP for each iteration as seen by user i is based on the transmission

power of each user not in user i's cell divided by its estimated pathloss to user i's base

station j . It is assumed that there is negligible cross-channel interference within each

cell. This ISCP estimate is, preferably, used in an open loop type analysis to

determine user i's power level for each iteration. One approach to calculated each k^

iteration's power level for user I (74), is per Equation 7.

M +l Equation 7

- PL_lt] - SIRr_j

A=l,ήgΩ( 7) If the location of each user is know, the pathloss can be estimated using the user's

location. Otherwise, the pathloss is estimated based on a typical expected pathloss

between that user's cell and user i's base station adjusted by the pathloss to that user's

base station. Alternately, user i's base station i may calculate that user's pathloss.

[0038] To facilitate implementation of the iteration analysis, each iteration can

be viewed as a vector multiplication, such as per Equation 8.

T^κ =A-T κ-\ Equation 8

A is an (M + 1) x (M + 1) matrix. In matrix A, an element A_M, where k is the row and

1 is the column and (1 ≤k, 1 ≤ M + 1) is given, such as per Equation 9.

0, where £ eΩ(;),/ GΩ(;^')

"^■u — (SIR_UL(k)-PL_k )l PL , where k eΩ(j),l ≡Ω(h),j≠h

Equation 9

[0039] The iterations are continued until the transmission power levels

converge (76), such as per Equation 10.

≤δ, where l≤i≤M +1 Equation 10 δ is a convergence parameter, which is a small number, such as 1 x 10^"4. Alternately,

a limit may be set to the number of iterations.

[0040] After convergence is met, each UE's estimated transmission power is

checked against its capabilities . If all users have acceptable transmission power levels,

the new user or service can be added (78). If some of the users exceed their

capabilities or are unacceptably close to their capability limits, the new user or service

is not admitted (78).

[0041] For the downlink time slots, the initial downlink transmission power

levels are used to produce a downlink transmission power vector T° (72), such as per

Equation 11.

7/°(l) T°(2)

T = Equation 11

T°( M ) T°( M +1)

The M + 1 user is proposed to be admitted to the N* base station. The values for

T°(i), . . . T°(M) are known or measured at their respective base stations 20. T°(M +

1) is determined such as per Equation 12. +1) = PL_M+ -ISCP_M+l -SIR_DL(M +1) Equation 12

[0042] PL_{M +} , _n is the measured pathloss between base station n and user M +

1 or the pathloss is estimated based on other users similarly situated. ISCP_M+1 is the

measured ISCP or another interference measure at user M+1, prior to admission.

This value may also be estimated based on other users similarly situated. SIR_DL(M +

1) is the desired received downlink SIR at user M+1.

[0043] Each user's downlink power level is iteratively estimated (74), after

introduction of the new user M + 1. One approach to calculate each K"¹ iteration for

an i* user is per Equation 13.

T^K(i)=PL_i ISCP^K-^l(i)-SIR_DL(i)

M+l Equation 13

= PL_i SlR_DL(i)- (T^κ-^l(h)IPL_L )

AeΩ( ), =l, 2,...,N,L≠j

L represents all other base stations 20 besides base station j of the i^Λ user. To facilitate

implementation, determining each iteration, K, can be viewed as a vector

multiplication such as per Equation 14. T^K=B-T^K~l Equation 14

T^κ is the determined transmission power levels. T^κ_1 is the determined power level of

the preceding iteration. Bisa(M+l)x(M+l) matrix. For an element at the r^ώ row

and s^¹ column of B, such that 1 < r, s ≤ M + 1), B_rs is determined per Equation 15.

r≡Ω(j),seΩ(j)

*« = Equation 15

(SlR_Dl(r)-PL_r.)IPL_r<i reΩiJ),s≡Ω(l) ≠l

The iterations are continued until the transmission power levels converge (76), such

as per Equation 16.

where l≤i≤M +1 Equation 16

δ is a convergence parameter, which is a small number, such as 1 x 10^"4. The

convergence parameter for the downlink may be the same or different than the uplink

convergence parameter. [0044] After convergence is met, estimated downlink transmission power is

checked against the base station's transmission capabilities. If all transmitters 50 will

be within acceptable transmission power levels, the new user can be admitted (78).

If some of the transmitters 50 exceed their transmission power level limit or are

unacceptably close to the limit, the new user is not admitted (78).

[0045] In some systems, all of the measurements required for the procedure of

Figure 6 may not be available. One approach to determine the increase in

transmission power as a result of a new assignment using noise rise is per Figure 7.

The noise rise as a result of an assignment depends on the pathloss, the measured

interference (I), such as measured using ISCP, and the SIR target for the transmitter

of interest. As a result, empirically, the noise rise can be estimated.

[0046] The noise rise is modeled as a variable depending on the pathloss, the

measured interference, and the SIR target. Using either simulation or field data, a

noise rise model is developed (80). The data can be collected and updated during the

system normal operation. The modeled noise rise may be stored as a table or a

mathematical relationship (82), such as a curve or series of curves.

[0047] One equation for estimating noise rise is per Equation 17.

Noise rise = Δ I (I, pathloss, SIR_TARGET) Equation 17

[0048] The noise rise is modeled as a change in the measure interference (I), Δ

I. Δ I is a function of the measured interference, the pathloss and the target SIR. Figures 8 and 9 illustrate obtaining a curve fitting the noise rise using simulation

results for only the pathloss for simplicity. Data for the noise rise estimation can be

obtained, including during the system normal operation, in the following way.

Initially, a high fixed margin is used for resource allocation. Before every allocation,

the interference level is recorded. After allocation, allowing the power control loops

to adjust, the interference is measured again and compared to the before allocation

value. The difference is tabulated as a function of the pathloss to the user, the before

allocation interference and the required target SIR of the user. After a sufficient

number of collections, a smoothing operation is used to create a final table or

mathematical relationship, such as a formula.

[0049] Alternately, a generic table or mathematical relationship , such as

derived from simulations, is used. The generic table or relationship is refined or

updated during the normal system operations.

[0050] Figure 8 illustrates the simulated results of noise rise versus the pathloss.

Figure 9 illustrates a curve representing the noise rise versus the mean pathloss. As

a result, the noise rise for a transmitter can be estimated from that transmitter's

pathloss.

[0051] The transmitter power level for a transmitter is determined using the

estimated noise rise, such as per Equation 18.

Transmit Power = Interference Measure + Pathloss + SIR_TARGET

+ Noise Rise + Measurement Error Margin

Equation 18 The Measurement Error Margin is a design parameter used to compensate for

measurement errors. The Measurement Error Margin is typically set at a

conservatively high value to allow an adequate margin.

[0052] Under certain conditions, information concerning the transmitter's

pathloss may not be available, as shown in Figure 10. Missing pathloss information

may result in uplink time slots, where the UE transmission power level is unavailable

for the pathloss calculation. To estimate the noise rise in such situations, a

conservatively high stipulated value for the pathloss, pathloss , is used (84). Using

a high stipulated value, effectively overestimates the noise rise. Accordingly, the

resulting determined transmission power levels are typically overstated. The noise rise

is determined using Equation 19.

Noise Rise = Δ I (I, pathloss, SIR_TARGET) Equation 19

The stipulated value for the pathloss maybe a set value or a cell dependent parameter

based on cell range and propagation conditions.

Claims

CLAIMSWhat is claimed is:

1. A method for estimating a transmission power level of a selected user

in a code division multiple access communication system, the method comprising:

providing a model for noise rise of users in relation to an interference measure,

a pathloss and a desired signal to interference ratio;

determining a pathloss and a desired signal to interference ratio for the selected

user;

determining a noise rise for the selected user using the determined interference

measure, pathloss, desired signal to interference ratio and the noise rise model; and

estimating the selected user transmission power level using the determined

noise rise.

2. The method of claim 1 wherein the estimated selected user transmission

power level is estimated in part by adding the interference measurement, the pathloss

and the desired SIR of the selected user to the determined noise rise.

3. The method of claim 2 wherein a measurement error margin is included

in the estimated selected user transmission power level.

4. The method of claim 1 wherein the interference measure of the selected

user is measured using ISCP.

5. The method of claim 1 further comprising generating the noise rise

model and storing the noise rise model as a table.

6. The method of claim 1 further comprising generating the noise rise

model and storing the noise rise model as a mathematical relationship.

7. The method of claim 1 wherein the determined pathloss for the selected

user is measured.

8. The method of claim 1 wherein the determined pathloss for the selected

user is a stipulated value which overestimates a pathloss.

9. The method of claim 1 wherein the system is a time division duplex

communication system using CDMA and the selected user estimated transmission

power level is for a single time slot.

10. A radio network controller (RNC) for estimating a transmission power

level of a selected user in a code division multiple access communication system, the

RNC comprising:

a radio resource management device for determining an interference measure,

a pathloss and a desired signal to interference ratio (SIR) for the selected user,

determining a noise rise for the selected user using the determined interference measure, pathloss, desired SIR and a noise rise model, and estimating the selected user

transmission power level using the determined noise rise; wherein the noise rise model

uses variables including an interference measure, a pathloss and a desired SIR.

11. The RNC of claim 10 further comprising a measurement collection

device for receiving the interference measure, the pathloss and the desired SIR for the

selected user.

12. The RNC of claim 10 wherein the CDMA communication system is a

time division duplex communication system using CDMA and the estimating

transmission power levels is performed in a single time slot.

13. The RNC of claim 10 wherein the new user estimated transmission

power level is estimated by adding a pathloss, an interference measurement and a

target signal to interference ratio of the new user.

14. The RNC of claim 10 wherein the noise rise model is stored as a table.

15. The RNC of claim 10 wherein the noise rise model is stored as a

mathematical relationship.

16. The RNC of claim 10 wherein the determined pathloss for the selected

user is a stipulated value which overestimates a pathloss.

17. The RNC of claim 10 wherein the determined pathloss for the selected

user is measured.

18. A radio network controller (RNC) or estimating a transmission power

RNC comprising:

means for determining an interference measure, a pathloss and a desired signal

to interference ratio (SIR) for the selected user;

means for determining a noise rise for the selected user using the determined

interference measure, pathloss, desired SIR and a noise rise model, the noise rise

model uses variables including an interference measure, a pathloss and a desired SIR;

and

means for estimating the selected user transmission power level using the

determined noise rise.

19. The RNC of claim 18 wherein each last estimate is compared to a

transmission power level capability associated with the user of that last estimate to

determine whether to admit the new user.

20. The RNC of claim 18 wherein the system is a time division duplex

communication system using CDMA and the selected user estimated transmission

power level is for a single time slot.

21. A method for estimating a transmission power level of a selected user

in a code division multiple access (CDMA) communication system, the method

comprising:

determining an initial estimate of a transmit power level associated with the

selected user;

providing a transmit power level of users of the system other than the selected

user;

estimating subsequent estimates for the selected user and the other users using

previous transmit power level estimates of the selected user and the other users; and

repeating the estimating subsequent estimates with a last repetition' s estimated

transmit power levels for the selected and other users being the estimated transmit

power levels of the selected and other users.

22. The method of claim 21 wherein the initial estimate of the selected user

is determined using an estimated pathloss between the selected user and a base station

of the selected user, an interference estimate and a desired signal to interference ratio.

23. The method of claim 22 wherein the interference estimate is a measure

of interference signal code power of the selected user.

24. The method of claim 22 wherein the interference estimate is a measure

of interference signal code power of users situated similar to the selected user.

25. The method of claim 22wherein the estimated pathloss is a difference

between a received power level and a transmit power level of a communication of the

selected user.

26. The method of claim 22wherein the estimated pathloss is determined

pathloss of users similarly situated to the selected user.

27. The method of claim 21 wherein the estimating subsequent estimates for

each of the selected and other users is by using an estimated pathloss between users

of cells other than a cell of that user and a base station of that user, an interference

estimate and a desired signal to interference ratio.

28. The method of claim 27 wherein the interference estimate is determined

by summing a transmit power level of users of cells other than a cell of that user

divided by a pathloss between of the other cell user and that user's base station.

29. The method of claim 21 wherein the estimating transmit power levels

is repeated until the estimated power levels converge.

30. A radio network controller (RNC) for estimating a transmission power

level of a selected user in a code division multiple access (CDMA) communication

system, the RNC comprising:

means for determining an initial estimate of a transmit power level associated

with the selected user;

means for providing a transmit power level of users of the system other than

the selected user;

means for estimating subsequent estimates for the selected user and the other

users using previous transmit power level estimates of the selected user and the other

users; and

means for repeating the estimating subsequent estimates with a last repetition' s

estimated transmit power levels for the selected and other users being the estimated

transmit power levels of the selected and other users.

31. The RNC of claim 30 wherein the initial estimate of the selected user is

determined using an estimated pathloss between the selected user and a base station

32. The RNC of claim 31 wherein the interference estimate is a measure of

interference signal code power of the selected user.

33. The RNC of claim 31 wherein the interference estimate is a measure of

interference signal code power of users situated similar to the selected user.

34- The RNC of claim 31 wherein the estimated pathloss is a difference

selected user.

35. The RNC of claim 31 wherein the estimated pathloss is determined

pathloss of users similarly situated to the selected user.

36. The RNC of claim 30 wherein the estimating subsequent estimates for

estimate and a desired signal to interference ratio.

37. The RNC of claim 36 wherein the interference estimate is determined

38. The RNC of claim 37 wherein the estimating transmit power levels is

repeated until the estimated power levels converge.

39. A radio network controller (RNC) for estimating a transmission power

system, the RNC comprising:

a radio resource management device for determining an initial estimate of a

transmit power level associated with the selected user; for providing a transmit power

level of users of the system other than the selected user; for estimating subsequent

estimates for the selected user and the other users using previous transmit power level

estimates of the selected user and the other users; and for repeating the estimating

subsequent estimates with a last repetition's estimated transmit power levels for the

selected and other users being the estimated transmit power levels of the selected and

other users.

40. The RNC of claim 39 wherein the initial estimate of the selected user is

41. The RNC of claim 40 wherein the interference estimate is a measure of

interference signal code power of the selected user.

42. The RNC of claim 40 wherein the interference estimate is a measure of

interference signal code power of users situated similar to the selected user.

43. The RNC of claim 40wherein the estimated pathloss is a difference

selected user.

44. The RNC of claim 40wherein the estimated pathloss is determined

pathloss of users similarly situated to the selected user.

45. The RNC of claim 39 wherein the estimating subsequent estimates for

estimate and a desired signal to interference ratio.

46. The RNC of claim 45 wherein the interference estimate is determined

47. The RNC of claim 46 wherein the estimating transmit power levels is

repeated until the estimated power levels converge.